1. Field of the Invention
The present invention relates to certain [oxalylbis(iminophenylenecarbonylimino)]bis[hydroxynaphthalenesulfonic acids] and salts thereof, which are novel compounds useful as dental antiplaque agents and as inhibitors of connective tissue destruction.
2. Description of the Prior Art
Abnormal destruction of connective tissue by collagenase and/or neutral proteases causes tissue damage and/or tissue dysfunction. In these conditions an inhibitor of connective tissue destruction acting directly or indirectly would be useful in preventing, retarding, or reversing tissue damage and/or collagen diseases.
The term connective tissue refers to a matrix of at least three protein molecules, namely collagen, proteoglycan and elastin. These molecules play an important role in the structural integrity of normal tissues. Collagen, the most abundant protein in the body occupies a central position in the connective tissue matrix ["Biochemistry of Collagen", Ed. G. N. Ramachandran and A. H. Reddi, Academic Press, New York (1976); P. Bornstein, Ann. Rev. Biochem., 43, 567 (1974); J. Fessler and L. Fessler, Ann. Rev. Biochem., 47, 129 (1978)].
Collagen is, for example, the main structural component of the oral tissue (periodontal ligament, alveolar bone, gingiva, and cementum) [Fullmer, et al., J. Dental Research, 48, 646 (1969)]. Collagen amounts to 40% of cartilage protein, 90% of bone protein, and over 90% of dry dermis. Articular cartilage, the resilient tissue that covers the articulating extremities in synovial joints, consists of collagen fibers that are intimately meshed in a hydrated gel of proteoglycan.
Proteoglycan, as it exists in cartilage, is a molecule in which sulfated polysaccharide chains are covalently linked to a protein backbone ["Dynamics of Connective Tissue Macromolecules", Ed. P. M. Burleigh and A. R. Poole, North Holland, Amsterdam (1975)].
Elastin is a major connective tissue component of pulmonary structure ["Elastin and Elastic Tissue", Ed. L. B. Sandberg, W. R. Gray, and C. Franzblau, Plenum Press, New York (1977)]. The breadkown of elastin of pulmonary connective tissue is considered the primary event in pulmonary emphysema [A. Janoff in "Proteases and Biological Control", Cold Spring Harbor Conference on Cell Proliferation, 2, 603 (1975)].
Degradation of fibrous collagen is initiated by a combination of neutral proteases and tissue collagenase as an integral part of a complex immunopathological process which results in the loss of collagen from normal tissue. Under normal conditions cellular mechanisms maintain a careful balance between the rates of collagen synthesis and degradation. However, in certain pathological conditions, the ensuing elevated levels of neutral proteases and collagenase can result in rapid collagen degradation and tissue dysfunction. For example, in periodontal disease, the generated elevated levels of neutral proteases and collagenase in the gingival crevicular fluid rapidly degrade the fibrous collagen supporting the teeth. Periodontal pockets result ultimately from collagen degradation and, as these pockets deepen, support of the teeth is lost and alveolar bone is resorbed [K. Ohlsson, I. Ohlsson, and G. I. Basthall, Acta Odontol. Scand., 32, 51 (1974); L. M. Golub, S. Kenneth, H. McEwan, J. B. Curran, and N. S. Ramamurthy, J. Dental Research, 55, 177 (1976); L. M. Golub, J. E. Stakin and D. L. Singer, J. Dental Research, 53, 1501 (1974); L. M. Wahl, S. M. Wahl, S. E. Mergenhagen, and G. R. Martin, Proc. Natl. Acad. Sci. U. S., 71, 3598 (1974); Science, 187, 261 (1975)].
In arthritic conditions such as in rheumatoid arthritis, septic arthritis, and osteoarthritis, elevated degradation of collagen and proteoglycan initiate rapid destruction of articular tissue [J. M. Evanson, J. J. Jefferey, and S. M. Krane, Science, 158, 499 (1967); E. D. Harris, D. R. Dibona and, S. M. Krane, J. Clin. Invest., 48, 2104 (1969); E. D. Harris in Rheumatoid Arthritis, Medcom. Press, N.Y. (1974); Z. Werb, C. L. Mainardi, C. A. Vater, and E. D. Harris, New Eng. J. Med., 296, 1017 (1977); J. M. Dayer, R. G. Russell, and S. M. Krane, Science, 195, 181 (1977); E. D. Harris, C. A. Vater, C. L. Mainardi, and Z. Werb, Agents and Actions, 8, 35 (1978); D. E. Woolley, E. D. Harris, C. L. Mainardi, and C. E. Brinkerhoff, Science, 200, 773 (1978); E. D. Harris, C. S. Faulkner, F. E. Brown, Clin. Orthoped., 110, 303 (1975); M. G. Ehrlich, H. J. Mankin, H. Jones, R. Wright, and C. Crisper, J. Bone Jt. Surg., 57A, 565 (1975); S. Gordon, W. Newman, and B. Bloom, Agents and Action, 8, 19 (1978); "Mechanisms of Tissue Injury With Reference to Rheumatoid Arthritis", Ed. R. J. Perper, Ann. N. Y. Acad. Sci., 256, 1-450 (1975)].
Increased collagen degradation in bone can result in abnormal bone destruction as in osteoporosis [C. G. Griffith, G. Nichols, J. D. Asher, and B. Flannagan, J. Am. Med. Assoc., 193, 91 (1965); B. Gardner, H. Gray, and G. Hedyati, Curr. Top. Surg. Res., 2, 175 (1970); B. Gardner, S. Wallach, H. Gray, and R. K. Baker, Surg. Forum, 22, 435 (1971)]. Collagenase activity has also resulted in tissue damage in cholesteatoma [M. Abramson, R. W. Schilling, C. C. Huang, and R. G. Salome, Ann. Otol. Rhinol. Faryngol., 81, 158 (1975); M. Abramson and C. C. Huang, Larynogoscope, 77, 1 (1976)]. In corneal ulcerations that progress to loss of corneal integrity and function, collagenase has been implicated as a direct factor in corneal destruction [S. I. Brown, C. W. Hook, and N. P. Tragakis, Invest. Ophthamol., 11, 149 (1972); M. B. Berman, C. H. Dohlman, P. F. Davison, and M. Ghadinger, Exptl. Eye Res., 11, 225 (1971)]. Elevated levels of collagenase have also been observed in patients with epidermolysis bullosa and a group of related genetic diseases of the skin [E. A. Bauer, T. G. Dahl, and A. Z. Eisen, J. Invest. Dermatology, 68, 119 (1977).
Increased breakdown of elastin of the lung tissue by neutral proteases (elastase) may contribute to the lesions in pulmonary emphysema [I. Mandel, T. V. Darmle, J. A. Frierer, S. Keller, and G. M. Turino in Elastin and Elastic Tissue, Ed. L. B. Sandberg, W. R. Gray, and C. Franzblau, Plenum Press, N. Y., p 221 (1977)].
A variety of substances, both naturally occurring and synthetically prepared, have been found to be inhibitors of connective tissue destruction, e.g., inhibitors of collagen degradation, that is as collagenase inhibitors. Such substances include, for example, ethylenediaminetetraacetate, 1,10-phenanthroline, cysteine, dithiothreitol and sodium auriothiomalate [D. E. Woolley, R. W. Glanville, D. R. Roberts, and J. M. Evanson, Biochem. J., 169, 265 (1978); S. Seifter and E. Harper, Chap. 18, "The Collagenases" in The Enzymes (3rd. Edition), 3, 649-697, Ed. by P. D. Boyer, Academic Press, N. Y. (1971)].
In the eye, a number of studies using collagenase inhibitors directly applied to corneal ulcerations have been reported. Calcium ethylenediaminetetraacetate and acetylcysteine reduce the frequency of ulceration in the alkali burned rabbit [M. Berman and C. Dohlman, Arch. Ophthamol., 35, 95 (1975)]. Both cysteine and acetylcysteine have been effective in the treatment of acute and chronic corneal ulceration in the human, although the latter compound was preferred because of its greater stability [S. I. Brown, N. P. Tragakis and D. B. Pease, Am. J. Opthalmol., 74, 316 (1972); M. Berman in Trace Components of Plasma: Isolation and Clinical Significance, 7th Annual Red Cross Symposium, p. 225, Alan R. Liss, Inc., N. Y. (1976)].
Naturally occurring collagenase inhibitors include the serum components .alpha..sub.2 -macroglobulin and .beta..sub.1 -anticollagenase [D. E. Woolley, R. W. Glanville, D. R. Roberts and J. M. Evanson, Biochem. J., 169, 265 (1978)].
The deposition of dental plaque on teeth is considered to be a precursor to dental caries, gingivitis and periodontal disease. Therefore methods and compositions useful for the prevention, or inhibition of dental plaque formation on teeth are considered to be of major potential therapeutic importance.
Dental caries, which always begin on the external surfaces of the teeth, may be initiated by oral acidogenic bacteria which include Lactobacillis acidophilus and Streptococci, e.g., Streptococcus mutans, and yeasts capable of producing a pH of 5.5 or lower. Fermentable dietary carbohydrates serve as substrates for the microbial enzyme systems leading to the production of acidic metabolic products such as lactic, acetic, formic and butyric acids. Adherence of cariogenic bacteria such as Streptococcus mutans, and the like, to tooth enamel and their aggregation and colonization to dental plaque are prerequisites to the formation of carious lesions. Sucrose, cell wall polysaccharides, pellicle components of saliva and calcium, participate in the formation of the lesion. Colonization on the tooth surface may serve as an area favorable to the production of the acidic metabolic products hereinabove described, providing protection from the buffering action of the saliva and causing the dissolution of the enamel in the vicinity of the plaque area resulting in decalcification. Some proteolytic action on the organic structure may also take place.
Gingivitis, which is an inflammation of the gums characterized by congested, red and swollen gingivae, frequently may occur due to dental calculus as the sole cause.
Periodontitis, the most common form of periodontal disease is characterized by inflammatory tissue changes usually due to local irritation, which local causes include irritation resulting from calcareous deposits on the teeth.
In theory, dental caries can be prevented by eliminating cariogenic bacteria, especially Streptococcus mutans, from the mouth or by increasing the resistance of enamel to acid and/or the adherence of S. mutans to its surface.
Agents that bind to tooth components have, at least on a theoretical basis, a utility in the treatment of dental diseases [S. Hamada and H. D. Slade, Microbiol. Rev., 44, 331 (1980)]. Support of this view is derived from results obtained with chlorohexidine [G. Rolla, H. Loe and C. R. Schiott, Arch. Oral Biol., 16, 1109 (1971)]. These studies have shown that chlorohexidine, an antibacterial agent, binds to pellicle and/or tooth components and this binding may contribute, at least in part, to its long acting antigingivitis properties.
Fluoride, a known anticaries agent, is known to protect human tooth enamel from dissolution. Mechanistic studies indicate that fluoride binds to enamel and is incorporated into the hydroxyapatite fraction of the enamel. The resulting fluoroapatite is relatively resistant to acid.
U.S. Pat. No. 2,687,436 discloses substituted 3-(2-naphthyl)cyclohexanes useful in the treatment of collagen diseases. British Pat. Nos. 856,357 and 1,246,141, disclose 2-aryl-hexahydro-quinolizines and 1-hydroxylpraline derivatives, respectively, useful for treating diseases affecting connective tissue. The closest known structurally related compound to those of the present invention and disclosed as having collagenase inhibiting activity is found in Thromb. Res. 1977, 10(4), 605-11 wherein the trypanocidal agent trypan blue is reported as inhibiting the activity of collagenase, or a proteinase contaminant in the collagenase preparation. It is interesting, however, that in this same article, the ureide Suramin is reported as not inhibiting the action of collagenase. Ureides similar to those of the present invention, but not disclosed as inhibitors, are found in Journal of the Chemical Society, 3068 (1927), and in U.S. Pat. Nos. 1,218,654 and 1,308,071.
While some compounds may inhibit the destructive effect of collagenase on connective tissue by acting directly on collagenase itself, other compounds may inhibit such destruction by coating, binding or competing with sights on the connective tissue in such a manner as to prevent collagenase from attacking it. The present invention, however, is not to be restricted or limited to any particular mechanism or mode of action. Suffice it to say that the compounds of this invention have utility as inhibitors of connective tissue destruction albeit in whatever manner or mode.